1. Field of the Invention
The present invention relates generally to a connector that is connected to a counterpart connector by fitting. The present invention relates more particularly to a differential transmission connector.
2. Description of the Related Art
Data transmission systems include an ordinary transmission system and a differential transmission system. The ordinary transmission system employs an electric wire for each data item. The differential transmission system, using a pair of electric wires for each data item, simultaneously transmits a “+” signal to be transmitted and a “−” signal equal in magnitude and opposite in direction to the “+” signal. The differential transmission system, which has the advantage of being less susceptible to noise compared with the ordinary transmission system, is widely used in fields where signals are transmitted at high speed.
FIG. 1 is a schematic perspective view of a conventional differential transmission connector unit 1.
FIG. 2 is a schematic diagram illustrating a structure of the opposed faces of a plug connector 2 and a jack connector 3.
The differential transmission connector unit 1 includes the plug connector 2 and the jack connector 3. The plug connector 2 is mounted on a backplane (external board) 4. The jack connector 3 is mounted at an end of a daughterboard (external board) 5. The plug connector 2 and the jack connector 3 are connected so that the backplane 4 and the daughterboard 5 are electrically connected by the connector unit 1. (See, for example, Japanese Laid-Open Patent Application No. 5-275139.)
As illustrated in FIG. 1 and FIG. 2, the plug connector 2 includes multiple pairs of signal contacts (signal contact pairs) 252, multiple inverse L-letter shaped ground contacts 258 provided one for each signal contact pair, and a U-letter shaped insulative housing 8 that supports the signal contact pairs 252 and the ground contacts 258.
The signal contact pairs 252 are arranged in row directions (the X1 and the X2 direction) and in column directions (the Z1 and the Z2 direction) like a grid. Each of the signal contact pairs 252 includes a signal contact 254 and a signal contact 256 for transmitting positive and negative signals, respectively, having complementary waveforms in axial symmetry. The signal contacts 254 and 256 are arranged in the column directions. Each of the ground contacts 258 includes a horizontal plate part 258-1 and a vertical plate part 258-2 to cover a corresponding one of the signal contact pairs 252 on its Z1 side and X1 side. The horizontal plate parts 258-1 extend to the backside of the housing 8 to serve as terminal parts.
As illustrated in FIG. 1 and FIG. 2, the jack connector 3 includes an insulative housing 6, multiple modules 10, and multiple ground plates (shield plates) 111.
The insulative housing 6 includes openings 62-1 and 62-2 corresponding to the signal contacts 254 and 256, respectively, of the plug connector 2; and inverse L-letter shaped slits 62-3 corresponding to the ground contacts 258 of the plug connector 2.
The modules 10 are arranged in the row directions. Each of the modules 10 includes four signal contact pairs 152, which are arranged in the column directions. Each of the signal contact pairs 152 includes a signal contact 154 and a signal contact 156 for transmitting positive and negative signals, respectively, having complementary waveforms in axial symmetry. The signal contacts 154 and 156 are arranged in the column directions. The ground plates 111 are provided one between each adjacent two of the modules 10.
FIG. 3 is a schematic cross-sectional view of an electrically connected portion of the plug connector 2 and the jack connector 3.
The plug connector 2 and the jack connector 3 are electrically connected with the housing 8 being fit into the housing 6 to have the signal contacts 254 and 256 inserted into the housing 6 through the openings 62-1 and 62-2 to be in contact with the signal contacts 154 and 156, respectively.
At this point, the ground contacts 258 are inserted into the housing 6 through the corresponding slits 62-3 to have the vertical plate parts 258-2 and the horizontal plate parts 258-1 placed on the X1 side and the Z1 side, respectively, of the corresponding electrically connected portions of the signal contact pairs 252 and 152.
According to this configuration, each adjacent two of the connected signal contact pairs 152 and 252 are partitioned by a corresponding one of the ground plates 111 and a corresponding one of the ground contacts 258. Accordingly, it is possible to suppress crosstalk between adjacent signals and transmit signals at high speed.